The present invention relates to a manifolding structure providing a by-pass passageway for a fluid flowing through an element such as a fluid filter upon detection of excessive fluid heat at the inlet of the element.
There are many fluid operated devices wherein a working fluid constantly flows into an operating device which causes heating of the fluid, the fluid being subsequently circulated through a cooler from which it is returned to the operating device. Such an arrangement may be used in internal combustion engines or machinery lubrication systems, and more particularly such an arrangement is provided in fluid clutches and automatic transmissions, such as automobile and truck automatic transmissions and the like. In fluid clutch and automatic transmission installations, a working fluid is caused to flow through a filtering element disposed between an outlet from the cooler and an inlet into the clutch or transmission housing. The filtering element is designed to remove from the fluid metallic and non-metallic particles, ashes, residues and other contaminants. The filter element causes a pressure drop which in turn decreases the flow of fluid from the cooler to the clutch or transmission housing and back to the cooler, even though the filter element may be substantially clean and unclogged. With usage, the pressure drop across the filtering element increases, because of progressive clogging of the element, which further reduces the flow of fluid through the cooler. This in turn causes overheating of the fluid, loss of applied pressures to the co-operating elements of the clutch or transmission, and a high incidence of major failure of mechanical components of the clutch or transmission. Even when the filter element is relatively new, thus offering a minimum amount of resistance to the passage of fluid therethrough, overload such as caused by pulling an excessively heavy trailer or overloading a truck or trailer, or lengthy hill-climbing under load, causes overheating of the transmission fluid, the overheating being further increased due to the pressure drop across the filtering element that reduces the fluid flow rate through the cooler.